1. Field of the Invention
This invention is related to the field of clocked storage devices such as flops, latches, registers, etc.
2. Description of the Related Art
The operating frequency of processors and other digital integrated circuits has continued to increase, reaching the GigaHertz (GHz) range in recent years. As the frequency has increased, the delay attributable to the clocked storage devices used to store state at the clock cycle boundaries has grown to a larger percentage of the clock cycle time. Accordingly, the amount of time available to do “useful work” has decreased.
Similarly, clocked storage devices typically support scan functionality for test purposes. The clocked storage devices may be linked together through special scan-in inputs and scan-out outputs in one or more “scan chains”. State can be scanned in and out of the clocked storage devices for debugging and/or other test purposes. Often, the scan functionality also impacts the delay attributable to the clocked storage device.